Christopher Ritchlin, M.D., M.P.H, is a rheumatologist at the Psoriasis Center at University of Rochester and a member of the National Psoriasis Foundation Psoriatic Arthritis Design Committee. Here, he answers common questions about psoriatic arthritis:
Q: What impact do wheat and grain-free diets have on psoriatic arthritis?
A: I have very strong views on diets because of the experience we’ve had in our clinic and in the literature. The bottom line is that if you do not have celiac disease, and most people don’t, there’s no need to eliminate grains from your diet. It’s important that one use portion control and decrease caloric intake in a balanced way and maintain a reasonable level of activity. We recommend that you really look at the carbohydrate load and keep that down, but mainly look at your portions and your caloric intake to reasonably lose weight if you need to.
Q: Is there a way to tell the difference between pain from psoriatic arthritis and just plain getting old?
A: Psoriatic arthritis is an inflammatory form of joint disease, unlike osteoarthritis, which is noninflammatory. Generally, osteoarthritis pain tends to occur later in the day. It’s not associated with morning stiffness, joint swelling is generally not severe, and we don’t see redness or swelling like we do in psoriatic arthritis. Psoriatic arthritis tends to be worse in the morning. It’s associated with joint swelling and decreased range of motion, and tends to improve as the day goes on, in contrast to osteoarthritis, which tends to get worse as the day goes on.
Q: Is it possible that psoriatic arthritis, or other arthritis, would start in my shoulders and knees, for example, major joints rather than smaller joints?
A: Absolutely. We tend to emphasize the small joints of the hands and the feet because those are the most common joints we see involved, but shoulders, knees, cervical spine, lumbar spine, thoracic spine, and sacroiliac joints certainly are also sites that can be the early joints involved by psoriatic arthritis. Moreover, patients with psoriatic arthritis can develop something we call dactylitis, where a digit such as a toe or a finger becomes diffusely swollen and looks like a little sausage. Or they can develop something called enthesitis, a type of pain caused by inflammation at the places where tendons, ligaments, and joint capsules attach to the bone.
Q: Does the course of psoriatic arthritis symptoms wax and wane, relapse and remiss, or is it strictly a progressive condition?
A: In about 5 percent of patients, we can see true remission even without therapy, but that’s very unusual. As to whether it’s strictly a progressive condition, it really depends on how you define progression. As a rheumatologist, I define progression as progressive joint damage. In other words, we call this damage to the bone that can take the form of erosion, so little divots are appearing in the bone or there is a narrowing of the joint space.
If you look at that way of defining psoriatic arthritis, about 50 percent of patients from the time of diagnosis to two years will have damage in their joints on X-ray. If you follow them longer out, to eight or 10 years, that number is about 85 percent. But you have to remember that the patients who are seen by rheumatologists, especially at big academic centers, tend to be more severely involved. So our observations regarding progression on X-ray may be more severe than what is seen in a nonacademic population, meaning population out in the community.
Q: I have yellowing and thickening of my toenails. How can I tell if it is psoriatic disease or a combination of psoriatic disease and toenail fungus?
A: These can be distinguished in a dermatologist’s office. They will take a swab, and take a component underneath the nail with the swab, and put it in a liquid and look under the slide of a microscope. If you see little linear kinds of branching structures, these are hyphae that are associated with fungus. If you see that, it means that the nail problem in that particular joint is at least in part contributed to by a fungal infection. That doesn’t mean that there can’t be both psoriasis and fungus going on together. If that wet mount analysis on microscope is negative, though, it is likely that the nail problem is due to psoriasis.